ubifs_jnl_truncate(9)

💅 ubifs_jnl_truncate(9) — like, the kernel API manual entry, bestie 🎀

okay so this is ubifs_jnl_truncate, straight out of the Kernel API Manual bestie, and it's genuinely the moment a file gets shorter and the journal has to keep up ✨

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🌸 NAME 🌸

ubifs_jnl_truncate — update the journal for a truncation.

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🦋 SYNOPSIS 🦋

int ubifs_jnl_truncate (struct ubifs_info *c , const struct inode *inode
, loff_t old_size , loff_t new_size );

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💖 ARGUMENTS 💖

• c — the UBIFS file-system description object. your whole file-system's main character, fr fr 👑
• inode — the inode to truncate. yeah. that one. ✂️
• old_size — old size. the before pic 📸
• new_size — new size. the after pic 💅

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✨ DESCRIPTION ✨

so when the size of a file decreases due to truncation, a truncation node is written, the journal tree is updated, and the last data block is re-written if it has been affected 😭 like the last data block literally gets dragged back into the group chat. the inode is also updated in order to synchronize the new inode size — nobody's walking around with a stale size, not on her watch 🫶

this function marks the inode as clean and returns zero on success. in case of failure, a negative error code is returned. periodt. 💀

ngl bestie, success is 0 and failure is a negative error code — so like, don't go looking for a positive return value, it's not giving 🌈

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🔥 SEE ALSO 🔥

kernel file ./fs/ubifs/journal.c — and honestly the whole friend group shows up:

• zero_ino_node_unused(9)
• zero_dent_node_unused(9)
• zero_trun_node_unused(9)
• reserve_space(9)
• write_head(9)
• __queue_and_wait(9)
• wait_for_reservation(9)
• wake_up_reservation(9)
• add_or_start_queue(9)
• make_reservation(9)
• release_head(9)
• finish_reservation(9)
• get_dent_type(9)
• pack_inode(9)
• mark_inode_clean(9)
• ubifs_jnl_update(9)
• ubifs_jnl_write_data(9)
• ubifs_jnl_write_inode(9)
• ubifs_jnl_delete_inode(9)
• ubifs_jnl_xrename(9)
• ubifs_jnl_rename(9)
• truncate_data_node(9)
• ubifs_jnl_delete_xattr(9)
• ubifs_jnl_change_xattr(9)

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⭐ ok that's the whole page, no notes 💜 this one's from ./fs/ubifs, dated October 2026, and it's literally titled ubifs_jnl_truncate(9) — iykyk, slay, bye bestie 🧚🍓